Determination of Crude Fiber Content -A Complete Procedure (AOAC 978.10)

Summary

This video provides a detailed procedure for determining crude fiber content in food and feed samples. The process involves five key steps: boiling the sample in acid and base solutions, drying, incinerating the fiber, and calculating the fiber content. Key equipment includes a balance machine, furnace, hot plate, and hot air oven, along with sulfuric acid and sodium hydroxide solutions. The video explains how to prepare these chemical solutions, boil the sample, and accurately measure the fiber content, culminating in a clear calculation of the crude fiber percentage.

Takeaways

• 😀 The determination of crude fiber content is an essential part of proximate analysis for food and feed samples.
• 😀 The analysis involves five main steps: boiling in acid, boiling in base, filtering, drying, and incineration of fiber.
• 😀 To conduct the test, you'll need specific equipment such as a balance machine, muffle furnace, hot plate, and hot air oven.
• 😀 Two chemical solutions are used: 0.128 M sulfuric acid and 0.313 M sodium hydroxide.
• 😀 Preparing the sulfuric acid solution involves diluting concentrated sulfuric acid with distilled water to a final volume of 500 mL.
• 😀 For the sodium hydroxide solution, 6.25 grams of pellets are dissolved in distilled water to prepare a 0.313 M solution.
• 😀 The sample is first boiled in the sulfuric acid solution for 30 minutes, followed by filtering to separate the fiber.
• 😀 The sample is then boiled in the sodium hydroxide solution for another 30 minutes to remove additional components.
• 😀 After boiling, the fiber is collected, dried at 130°C for 2 hours, and then burned in a muffle furnace at 550°C.
• 😀 The crude fiber content is calculated by determining the weight difference between the fiber and the ash after incineration.
• 😀 The final crude fiber percentage is calculated using the formula: (W1 - W2) / Ws, where W1 is the weight of the fiber, W2 is the weight of the ash, and Ws is the sample weight.

Q & A

What is the purpose of determining crude fiber content in food and feed samples?

Determining crude fiber content is crucial for analyzing the nutritional value and digestibility of food and feed samples.

What are the five main steps involved in crude fiber analysis?

The five main steps in crude fiber analysis are: boiling in acid solution, boiling in base solution, drying fiber, incinerating the fiber, and calculating the crude fiber content.

What equipment is required for crude fiber analysis?

The equipment required includes a balance machine, muffle furnace, hot plate, hot air oven, measuring cylinder, funnel, crucible, conical flask, beaker, cotton cloth, marker pen, and spoon.

How is 0.128 M sulfuric acid solution prepared?

To prepare 0.128 M sulfuric acid, approximately 400 mL of distilled water is added to a volumetric flask, followed by 3.5 mL of concentrated sulfuric acid. The flask is then mixed and filled with distilled water to a final volume of 500 mL.

How is 0.313 M sodium hydroxide solution prepared?

To prepare 0.313 M sodium hydroxide solution, 6.25 grams of sodium hydroxide pellets are dissolved in approximately 400 mL of distilled water in a volumetric flask. The flask is then filled with water to a final volume of 500 mL.

What is the role of sulfuric acid in the fiber analysis process?

Sulfuric acid is used to boil the sample in an acid solution, which helps to remove soluble components, leaving behind the crude fiber.

Why is sodium hydroxide used in the fiber analysis process?

Sodium hydroxide is used to boil the sample in a base solution, which further helps to remove additional soluble components, ensuring the crude fiber is isolated.

How is the sample filtered after boiling in acid and base solutions?

After boiling, the sample is filtered using a cotton cloth and funnel to separate the fiber from the liquid. The filtrate is then washed with hot water to remove residual acid or base.

What temperature and duration are required for drying the fiber?

The fiber is dried in a hot air oven at 130°C for 2 hours to remove any remaining moisture.

How is the crude fiber content calculated?

The crude fiber content is calculated by weighing the crucible with fiber before and after incineration. The difference in weight is used along with the sample weight to calculate the crude fiber percentage.